docs: def Heartbeat(self):
      """Sends a heartbeat to the Fleetspeak client.
  
      If this daemonservice is configured to use heartbeats, clients that don't
      call this method often enough are considered faulty and are restarted by
      Fleetspeak.
      """
      heartbeat_msg = common_pb2.Message(
          message_type="Heartbeat",
          destination=common_pb2.Address(service_name="system"))
      self._SendImpl(heartbeat_msg)